Welding apparatus



April 3, 1945.

H. T. PLATZ .WELDING APPARATUS Filed Aug. 10, 1956 v FIGJ. 0

20 a 21 n 27 2a 22 29 24 FIG.3A.

4 Sheets-Sheet l INVENTOR HENRY T. PLATZ Wm A WH Ml;

A TTORNEYS April 3, 1945. PLATZ 2,372,850

WELDING APPARATUS Filed Aug. 10, 1936 4 Sheets-Sheet 2 s 42 I h o I" o 31 FIG.9. 45 C) V a? L i a F IGJO.

INVENTOR HENRY T. PLATZ ATTORNEYS April 3, 1945. H. T. PLA TZ 2,372,850

WELDING APPARATUS Filed Aug. 10, 1936 4 Sheets-Shet. 3

FIG.8.

INVENTOR HENRY T. PLATZ Y WMMMMM A TTORNEYS April 3, 1945 H, T P ATZ 2,372,350

WELDING APPARATUS Filed Aug. 10', 1956 4 Sheets-Sheet 4 F INVENTOR D as HENRY T. PLATZ w A BY I a 32 uW/Wf-M ATTORNEYS Patented Apr. 3, 1945 WELDING APPARATUb Henry T. Platz, Detroit, Mich., assignor to Briggs Manufacturing Company, Detroit, Mich., a

corporation of Michigan Application August 10, 1936, Serial No. 95,244 '1 Claims. (Cl. 219-4) This invention relates generally to welding apparatus and refers more particularly to a unit for automatically controlling 'the operation of welding devices.

One of the principal objects of this invention resides in the provision of welding equipment having a welding device and having means for automatically controlling the operation of the welding device to enable the operator to complete a series of welds in a relatively short time with the minimum effort and attention.

Another object of the present invention resides in the provision of a welding device control unit effective upon manipulation of a control element to automatically and successively start a weld, discontinue said weld after a predetermined interval of time elapses, and to start another weld in timed relation to discontinuing the weld aforesaid.

' In accordance with this invention, the control unit responds to manipulation of. the control element to successively eiiect the following operations; relative movement of the electrodes into engagement with the work; operationof a switch to close the welding circuit to the electrodes after the latter are in engagement with the work; operation of the switch to open the circuit to the electrodes after a predetermined interval of time elapses, and thereafter permitting relative move ment of the electrodes awa from each other to isengage the same from the work. Upon relative movement of the electrodes away from the work, the control unit starts another weld by successively repeating the foregoing operations, and this continues so long as the control element is retained in its operative position.

Another advantageous feature of the present invention resides in the provision of means for varying the duration of the weld and for varyin the elapsed time between the successive welds.

A further object of this'invention consists in the provision of a control unit embodying means for varying, the time of closing of the circuit to the electrodes with respect to relative movement of the latter into engagement with the work, and alsohaving means for varying the interval of operation of the switch to open the circuit to the electrodes.

The foregoing, as well as other objects, will be made more apparent as this description proceeds, especially when considered in connection with the accompanying drawings, wherein- Figure 1 is a front elevation partly in section of a control unit constructed in accordance with this invention;

Figure 2 is a. side elevational View of a weldin device having certain parts broken away for the sake of clearness;

Figure 3 is a vertical longitudinal sectional view through thecontrol unit;

Figures 3A, 4, 5, 6, 7, 8, 9 and 10 are, respectively, sectional views taken substantially on the planes indicated by the lines 3A3A, 4-4, 5-5,

6-6, 1--'|, 8-8, 9 '9 and Ill-l0 of Figure 1;

Figures 1 1 and 12 are diagrammatic views showing the parts of the welding equipment in various different positions.

A general description of the welding equipment forming the subject matter of this invention may expedite an understanding of the detailed construction and, with this in mind, attention is directed to the diagrammatic views illustrated in Figures 11 and 12. Referring first to Figure 11, it will be noted that the welding dc Vice A is of the gun type having an electrode B movable toward a fixed electrode C under the action of fluid pressure against a piston D reciptudinally extending passage K intermediate the ends of the latter. The passage K is provided with metering valves L and L at opposite ends thereof communicating respectively with valve chambers M and M disposed at opposite ends of tlce plunger chamber N.

'- In the position of the parts shown in Figure 11, fluid under pressure from the passage K is prevented from flowing into the chamber M by a piston valve O'-;' with the result that all of the fluid under pressure is required to flow in the direction of the arrows in Figure 11. As shown in this latter figure, the piston valve 0 in the chamber M is in a position to permit metered flow oi fiuid pressure into the chamber M in advance of the piston O, and from this chamber the fluid under pressure passes into an accumulating chamber P through a passage-Q. As will be more fully hereinafter set forth, the accumulating chamber P communicates with the outer end of the chamber M through a passage R in O der to buildup a pressure against the rear side I switch chamber.

latter offers a greater area to the action of the fluid pressure than the area of the valve piston presented to the fluid under pressure in the accumulating chamber i", there is a tendency for the plunger to move to the left at a faster rate than the valve piston 0-.

However, it will be noted from Figure 11 that the plunger is temporarily prevented from moving to the left under the action of the fluid pressure admitted to the chamber M by the com-' parativel-y unrestricted flow of fluid pressure through the supply line T. The supply line T communicates with the passagelK in advance of the metering valve L and also communicates with the cylinder E in the gun device through an annular chamber formed by reducing the plunger use similarto the plunger a, and connected thereto for movement therewith as a unit. The exhaust opening A is closed during the operation or the welding apparatus to effect the weld. by means The interval the plungers are moved from the position thereof illustrated in Figure llto the one shown in Figure 12, is controlled by regulating the rate of pressure rise in the chamber M at the right-hand end of the plunger 8 by the meter= in'g valve L. As soon as the pressure of the fluid acting upon the outer end or the plunger S be- 1 comes sufiicient to overcome the action of the fluid pressure in the groove U on the relatively small area of the plunger 8, the latter together with the plunger 5, is moved to the position 8 intermediate the ends thereof. As the pressure of the fluid builds up in the cylinder E at the rear side of the piston D, the latter is moved forwardly and eil'ects a displacement of the electrode B toward the electrodeC to clamp the work to be welded therebetween.- At the samev time, fluid under pressure is admitted from theisupply line T to a longitudinally extending passage V, 1 communicating with a switch W and a pressure accumulating chamber X. The fluid pressure admitted to the "switch W from the passage V serves to close an electric circuit to the electrodes in timed relation to relative movement of the latter into engagement with the work, and this in- .terval is controlled by a metering valve Y located in the fluid supply line to regulate the flow of fluid under pressure from the passage V to the The accumulating chamber X communicates with the opposite side of the switch, andthe fluid pressure in this chamber serves" to automatically open the switch W after a predetermined interval of operation of the .welding device. The length of the weld is controlled by regulating the rate of pressure rise in the accumulating chamber X through the medium of a metering valve Z. Thus, from the foregoing, it will be noted that when the control unit is in the position'thereof shown in Figure 11, the electrodes are relatively moved into clamping engagement with the work 0. Of course, when the plunger S is in thepo sition shown in Figure 12, the same closes comto be welded, and the welding circuit is automati-' cally closed by fluid pressure from the same source of supply, through the medium of the ber X for the purpose of automatically opening the switch W after a predetermined interval of weld,land this time interval is accurately controlled by regulating the pressure .rise in the chamber X through the medium of the valve Z.

After the weld has been complete'dor, in other words, after the switch W is automatically operated to open the circuit to the electrodes, the latter are relatively moved in directions away from each other to release the work, and this opera-' tion is eflectedjin dependence upon exhausting the fluid pressure from the cylinder E in the welding device. Referring again to Figure 11, it will be noted that the longitudinal passage V communicates with an exhaust Opening A throughthe medium of the control plunger S",

thereof shown in Figure 12, wherein the exhaust opening A communicates with the passage V, through the medium of the groove U in the plunger 8, and the fluid pressure flows inthe direction of the arrows indicated in Figure 12. Attention is called to the fact, that as the plunger 8 is moved from the position shown in Figure 11 to the one illustrated in Figure 12, the rear end portion thereof uncovers the exhaust ports B communicating with the plunger chamber N. As the exhaust ports B are uncovered, the drop in pressure in advance ofthevalve piston O is greater than the drop in pressurein the accumulating chamber P, with the re 12, wherein communication between the passage K and chamber M is closed by the valve piston munication through the supply line T and, if the valve}! is retained. in its open position, fluid pressure is conducted through the metering valve L to the chamber M at the outer side of the plunger S. This communication is established when the plunger S" is moved to the left sufliciently to effect a. movement of the valve piston O' to its extreme outermost, position shown in Figure 12. With the parts of the control unit G in the above position, fluid under pressure is being built-up at the outer side of the plunger S at -a rate dependent upon the adjustment of the metering valve L and, at the same time, the

welding apparatus including the welding device A, accumulating chamber X and switch W, are

exhausted through the opening A.

When the pressure in the accumulating chamber P becomes sufiicient to overcome the action of the spring C, the welding operation is reheated by the return of the plungers to the position thereof shown in Figure 11. Upon return of the plungers, the accumulating chamber P exhausts through the ports B", and the valve piston 0 again closes communication between the passage K and the valve chamber M. Also the plunger S closes the exhaust A, and this cycle of operation is repeated so long as the operator-retains the valve H, at the welding device, in its open position. In the event that the operator should effect a closing of the valve H when equlpment, selected herein for the purpose of illustration, it will be noted that the gun unit A is entirely independent of the control unit G, and

as'zasuo throughout their final portion of travel. In other words, as the end of the spring operatively connected to the plungers crosses a vertical plane including the axis of the pin 40,, continued fashioned to provide the cylinder E, and formed with a passage 2| communicating at one end with the cylinder E at the rear side of the piston D reciprocably mounted in the cylinder. The opposite end of the passage 2| communicates with the supply line T through the medium'of a flexible conduit .22. In addition, the frame is formed with a valve chamber23 communicating at one end with the passage J through the medium of the flexible conduit 24, and communicating intermediate the ends with a passage 25 extending through the grip 26 of the gun unit for communication with the fluid supply line F. The flow of fluid pressure from the supply line through the chamber 23' to the conduit 24 is controlled by a Piston valve 21 reciprocably mounted in the chamber 23 and having an annular. groove in the Periphery thereof registrable with the passage 25 in the outermost position of the valve piston 21. The annular groove communicates with an axially extending passage 28 through the valve pistonfor communication with the'conduit 26, and the piston is normally urged in an inward direction to close the passage 25 by means of a spring 29 acting upon the-outer end of the piston. In the present instance, the valve piston 21 is held in its outermost position, wherein com munication is established between the supply line and control unit G, by means of the trigger I pivotally supported on the frame 20 in the trigger guard 3|. Attention may be called to the fact at this time that when the trigger is released, the spring 29 locates the valve piston 21 in a position wherein the annular groove in the periphery thereof communicates with the exhaust passage D' in the frame 20 to connect this passage with the control unitthrough the conduit 24.

As stated above, the piston D is reciprocably mounted in the cylinder E, and it will be noted from Figure 2 that the piston carries the electrode B for moving thc'latter toward the electrode C. The .electrode C is secured to a fixture 32, and the latter in turn is secured to the frame 20 in any suitable manner. In the present instance, theelectrode B is moved in a direction away from the electrode C by the springs 33 acting upon the front side of the piston to resist movement of the latter by the fluid pressure in the cylinder E. It follows, therefore, that when the cylinder E is exhausted, the springs 33 act upon the piston D to disengage the electrodes from the work supported therebetween.

The control unit G is shown in Figures 1 and 3 to 9, inclusive, as comprising a compact casting 34 fashioned to house the control plungers and the switch W. Upon reference to Figure 3, it will be noted that the plunger cylinder N is formed by two axially spaced aligned bushings 35 secured in a bore 36 extending longitudinally through the casting and closed at opposite ends by means of thenuts 31 and 38; The casting 34 -is cored out between the adjacent ends of the bushings to provide a recess 39 for receiving the spring C having one end fixed to the casting in the recess, as at 40. The other end of the spring is operatively connected to the plungers for the purpose of accelerating movement of the plungers movement of the plungers is effected at a relatively fast rate.

The operative connection between the spring and plungers comprises a link 4| having the opposite ends respectively pivotally connected to the adjacent ends of the plungers and having the intermediate portion thereof extending between the furcations 4i ofa bifurcated arm 42.. The arm 42 is pivotally connected to the casting 34 in the compartment 39 for swinging movement by a shouldered stud 43, and the swinging end of the arm is connected to the spring, as at 84. It will be apparent from Figure 3 that the iurcations of the lever 12 extend between the adjacent ends of the plungers and engage the latter ends to permit movement of the plungers by the spring C. Inasmuch as the link 4| interconnects the adjacent ends of the plungers, it necessarily follows that both of the latter move as a unit, and I prefer to form the plungers of two sections instead of one in order to avoid the necessity of exercising extreme accuracy in aligning the bushings 35.

It Wllill readily' apparentfrom the several views of the casting 34 in the drawings, that the latter is also fashioned to provide the accumulating chambers P and P, aswell as the required assages for effecting the flow of the fluid under pressure previously described. Inasmuch as the function of the above accumulating chambers and required passages has been defined with some particularity in connection with the diagrams identified on the drawings by Figures 11 and 12, it is not believed necessary to complicate this description with a detailed definition as to the specific-arrangement of these passages in the casting 34.

The switch assembly W is also carried by the casting 34, and the specific construction of this switch assembly is shown and described in detail in my copending application, Serial No. 690,250, filed September 20, 1933. Briefly, the switch assembly W comm-lees a pair of stationary contacts 50 adapted to be bridged by a movable contact member 5i normally urged in a direction away from the static-nary contacts by means of the spring 52; Upon'reference to Figure 3; it will be noted that the bridge member 5| is slidably supported in a chamber 53, and i provided with an enlargement 54 at the inncr'end thereof adapted toextend into a fluid pressure chamber 55. The

fluid pressure chamber 555 communicates with the fluid pressure supply line through the medium of the metering valve Y, and as soon as the pressure in the chamber 55 exceeds that exerted by the sprin 52, the member 5| is moved outwardly to bridge the contacts 50. The ,contacts 50 are arranged in a circuit controlling the flow of Welding current to the electrodes, andbridging the same by the member 5| effects the weld. As

hereinb'efore stated, the metering valve Y is so adjusted that the welding circuit is, not closed until the electrodes are relatively moved into clamping engagement with the work.

In order to automatically move the contact member 5| in a direction away from the stationary contacts to open the -'welding"'cir. cult, the chamber 53 communicates with the :supply vline through the medium of-the accumulating chamberv X and the metering valve Z. The lo cation of the metering valve Z is such as to relong as the strict the flow of fluid under pressure into the accumulating chamber X, and the latter com municates directly with the switch member 53 through the passage 5'6. Ihe arrangement is such that when the fluidpressure in the chamber 58 approaches thefluid pressure in the chamber 55,

mum attention, on the part of the operator. It

will also be noted that my improved control unit is equipped with means for not only varying the rate at which the welds are effected, but for also varying the duration of each weld.

What I claim as my invention is:

1. In a repeat welder, a movable electrode connected in an electric circuit, a switch in said circuit, fluid pressure operated means for moving the electrode in one direction and for operating the switch, a manually operable member for ad mitting fluid pressure to the respective fluid pressure operated means, a valve intermediate the manually operable member and fluid pressure operated means, and fluid pressure cylinder for respectively moving the valve in opposite directions during manual operation of said member to continuously operate the electrode and switch in proper timed relationship.

2.' In a repeat welder, a movable electrode connected in an electric circuit, a fluid pressure operated cylinder for moving the electrode into engagement with the work to bewelded, mean for moving the electrode out of engagement with the work when the fluid pressure is released, a switch in the electrode circuit, fluid pressure operated means for operating the switch in timed relation to movement of the electrode, means for automatically repeating the cycle of operations as long as the fluid pressure is on comprising a valve movable in opposite directions to successively admit fluid pressure to and exhaust the same from the electrode cylinder and switch, and fluid pressure operated cylinders for respectively moving the valve in opposite directions.

3. Ina repeat welder, a movable electrode connected in an electric circuit, a control switch in said circuit, a fluid pressure operated, device for moving the electrode in a direction. to engage the same with the work to be welded, a second fluid pressure operated device for operating the switch,

a valve movable in opposite directions for temporarily interrupting the flow to and releasing the fluid in the first. mentioned fluid operated devices to cause a repetition of the cycle of operations as fluid is permitted to flow, and fluid pressure operated cylinders for periodically moving the valve in opposite directions in properly timed relation to form a series of individual welds.

'4. In a repeat welder, a movable electrode con nected in an electric circuit, a switch in said cir-= cuit, a fluid pressure operated device for respectively operating the electrode and switch, a manually operated, member for admitting fluid under pressure to both the devices aforesaid, a valve movable in opposite directions for alternately admitting fluid to and exhausting the same from the fluid pressure operated devices, and means for successively and repeatedly moving the valve in opposite directions during manual operation of said member comprising fluid pressure operated cylinders disposed between the fluid pressure operated devices and manually operated member.

5. In a repeat welder, a movable electrode connected in an-electric circuit, a switch in said circuit, a fluid pressure operated device for respectively operating the electrode and switch, a manually operated member for admitting fluid under pressure to both .the devices aforesaid, a reciprocable valve movable in opposite directions to successively-admit fluid under pressure to and exhaust the same from the fluid pressure operated devices, and means for successively and repeatedly moving the valve in opposite directions during manual operation of said member including fluid pressure operated cylinders communieating with the manually operated means and having pistons respectively engageable with opposite ends of said valve for reciprocatin the same. I

6. In a repeat welder, a movable electrode connected in an electric circuit, a fluid pressure operated cylinder for moving the electrode into engagement with the work to be welded, means for moving the electrode out of engagement with the work when the fluid pressure is released, a switch in the electrode circuit, fluid pressure operated means for operating the switch in timed relation ,to movement of the electrode, means for automatically repeating the cycle of operations a long as the fluid pressure is on comprising a valve movable in opposite directions to successively admit fluid pressure to and exhaust the same from the electrode cylinder and switch, fluid pressure operated cylinders for respectively moving the valve in opposite directions, and adjustable means for controlling the flow of fluid under pressure to the last named cylinders to regulate the speed of successive welds.

7 In a repeat welder, a movable electrode connected in an electric circuit, a switch in said circuit, a fluid pressure operated device for respectively operating the electrode and switch, a

valve movable in opposite directions for alternately admitting fluid under pressure to and exhausting the same from the fluid pressure oper- HENRY T. PLATZ. 

